茶树海藻糖-6-磷酸合成酶基因(CsTPS)的克隆及表达分析

摘要

海藻糖-6-磷酸合成酶(trehalose-6-phosphate synthase,TPS)是海藻糖合成途径中的一个关键酶.目前,TPS基因的研究多数集中于细菌和真菌等,而对植物的研究较少.本实验通过对茶树(Camellia sinensis(L.)O.Kuntze)全器官转录组文库序列比对,获得一条与其他物种同源性较高的编码TPS基因的EST序列,通过RACE扩增后获得茶树TPS基因cDNA全长序列,命名为Cs TPS(GenBank登录号JQ742017).该基因cDNA全长3 125 bp,包含一个2799 bp的开放阅读框,编码932个氨基酸.多序列比对分析结果表明,Cs TPS基因编码的蛋白具有明显的TPS和TPP两个结构域.系统进化分析表明,其编码的氨基酸序列与拟南芥(Arabidopsis thaliana)、烟草(Nicotiana tabacum)和番茄(Solanum lycopersicum)等植物的TPS同源性较高,且CsTPS与拟南芥TPS1(AtTPS1)的同源性高于TPS2(AtTPS2)和TPS3(AtTPS3).qPCR分析显示,CsTPS基因在茶树不同组织器官中呈现差异性表达.低温诱导促使老叶和嫩叶中的CsTPS基因上调程度明显大于根系,表明CsTPS基因可能参与了茶树抗寒机制.%Trehalose-6-phosphate Synthase (TPS) is a key enzyme in the synthesis of trehalose in plants. At present, researches about TPS have mainly focused on bacteria and fungi but little about plants. An EST, having high homology with TPS gene from other organisms, was screened from the whole organic transcriptomic library of tea {Camellia sinensis (L.) O. Kuntz) and amplified through RACE technology to obtain the cDNA full-length of trehalose-6-phosphate synthase gene, named CsTPS (GenBank accession number: JQ742017). The cDNA full-length of CsTPS was 3 125 bp with a single 2 799 bp opening reading frame that predicted to encoded a 932 animo acid, which contained two obvious structure domains, TPS and TPP, through multiple sequences alignment. Phylogenetic tree indicated that the deduced animo acid sequence of CsTPS gene had a very high identity with TPS genes from other organisms such as Arabidopsis thaliana, Nicotiana tobacum and Solanum lycopersicum. And the holomogy between CsTPS and AtTPSl genes was higher than that of AtTPS2 and AtTPS3. Quantitative Real-time PCR analysis showed that differential expression level of CsTPS gene existed in different organs and upregulation of CsTPS gene induced by low temperature in mature leaf and immature leaf were obviously higher than that in roots, which revealed that CsTPS gene may involve in cold-resistant mechanism of tea plant.